6.AT.8 Lesson 8-2-part2 Apply Day · Practice
MASTERY CHECK
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8.2 · Part II

Application Practice for Today's Problem

Solve One-Step Addition and Subtraction Equations · Equation

Interactive Workbench & Models →
Name: Date: Period: Learning Goal:
■ CONCEPT SUMMARY & GUIDED NOTES: 8.2 · Part II
1Solving Addition & Subtraction Equations
2Strategy Model — step by step
  1. Identify operation on variable
  2. Use inverse operation: subtract to undo addition; add to undo subtraction
  3. Property of Equality: do same operation to both sides
3Mathematical Word Bank
  • Solve One-Step Addition and Subtraction Equations (Resolver ecuaciones de suma y resta de un paso) — Use one inverse addition or subtraction operation to isolate the variable.
  • Equation (Ecuación) — A math sentence with an equal sign showing both sides are the same.
  • Inverse operation (Operación inversa) — Two math actions that undo each other, like × and ÷.
  • Isolate (Despejar) — To get the letter by itself on one side.
  • Solution (Solución) — A number that makes the equation or inequality true.
  • One-step equation (Ecuación de un paso) — An equation you can solve in a single step using one inverse operation.
4Watch out
  • A common mistake is applying the same operation instead of the inverse — for example, solving x − 7 = 15 by subtracting 7 from both sides (getting the wrong x = 8) instead of adding 7 to both sides (the correct x = 22). Another common mistake is doing the inverse operation to only one side, like solving x + 6 = 14 by subtracting 6 from the left but forgetting the right side. Before you submit, name the operation shown in the equation, choose its inverse, apply it to BOTH sides, and check by substituting your answer back into the original equation.
  1. 1 MULTIPLE CHOICE

    Solve: m − 11 = 25

    1. Am = 36
    2. Bm = 14
    3. Cm = 25
    4. Dm = 275
    ✏️ Workspace & Solution Steps
  2. 2 MULTIPLE CHOICE

    A shirt costs $d. After a $15 discount, it costs $38. What is d?

    1. A$53
    2. B$23
    3. C$38
    4. D$45
    ✏️ Workspace & Solution Steps
  3. 3 MULTIPLE CHOICE

    Unlock Card 1: Solve x + 7 = 15.

    1. Ax = 8
    2. Bx = 22
    3. Cx = 7
    4. Dx = 105
    ✏️ Workspace & Solution Steps
  4. 4 MULTIPLE CHOICE

    Unlock Card 2: Solve n − 4 = 9.

    1. An = 13
    2. Bn = 5
    3. Cn = 36
    4. Dn = -5
    ✏️ Workspace & Solution Steps
  5. 5 MULTIPLE CHOICE

    Unlock Card 3: A vault held some clue tokens. After the detective added 16 tokens, there were 50. The equation is t + 16 = 50. How many tokens were there before?

    1. A34
    2. B66
    3. C16
    4. D800
    My work — one step per lineWhat I did to both sides
    1. 1LookWhat is done to the variable?
    2. 2UndoDo the opposite — both sides.
    3. 3SimplifyOne side at a time.
    4. 4CheckPut it back in.
📐 CER MATHEMATICAL PROOF MATRIX (CER 2.0) SMP.3 / Proof & Justification

Writing Task: Justify why your mathematical solution is accurate and complete.

C Claim
Starter: My mathematical claim is that the solution is...
E Evidence
Starter: The evidence from the model/table demonstrates that...
R Reasoning
Starter: This proves my answer because the standard mathematical definition of...
Student Mastery Self-Assessment:
1 · Need More Support
2 · Getting Closer
3 · Got It / Solid
4 · Master / Can Teach It